This is another take on a long-standing problem with most of today’s Radiology PACS: proprietary Data/Object Formats. It has been at least four years since Presentation States and Key Image Notes were included in the DICOM standard, yet the majority of PACS vendors continue to treat these key work products as proprietary objects. The most consistent excuse is “There are many more features on our engineering schedule considered to be more important to our users.”
I can almost believe that story, since I have found that most users are not aware of the implications of proprietary data objects. Since almost every PACS supports the creation and display of Presentation States and Key Image Notes, the fact that most PACS treat these as proprietary objects is lost on most buyers and eventual users. Provided that these objects are kept within a given PACS, there is no apparent negative to their being proprietary. The user may not experience a situation where the proprietary nature of these objects presents a problem.
The problem arises when the user of one of these proprietary PACS tries to forward study data to another Facility or Health System that is using a different PACS. Whether that other PACS is DICOM conformant or not, unless it is the same PACS, those presentation States and Key Image Notes cannot be transferred, accessed, or displayed. Physicians using the other PACS will not have the benefit of seeing exactly what the radiologist interpreting the study saw in the images or what he may have typed as a text message. The benefit of these “work products” is lost.
The problem also arises when a user of one of these proprietary PACS tries to copy study data to a CD/DVD. The proprietary work products either cannot be copied, or they cannot be accessed and displayed by another PACS. This is one of the reasons why there is so much consternation over the current CD/DVD copying solutions on the market. The vendors of these proprietary PACS typically have to place a copy of their own viewing software on these CD/DVDs, because their proprietary viewer is the only way to view their proprietary study data.
The real problem will manifest itself only after the user has decided to replace the proprietary PACS with the next PACS. Data migration services will typically migrate the study pixel data to the next PACS, but few of these services currently migrate any proprietary study-related data objects. To do so would require knowing where these objects were stored in the PACS, how to extract them and how to convert them to their DICOM counterparts. This extraction, conversion, migration is not being performed and as a result, those proprietary data objects are lost forever. The images are available for historical comparison in the next PACS, but none of the proprietary work products are available. Now imagine the implication of having to window and level all of these priors again, when they are recalled for viewing with the new images. Imagine not having the spine labels, and not having any other annotation or overlay graphics created when the prior was first interpreted. That’s working without benefit of prior information, or a possible expenditure of time redoing all that work.
A PACS should treat Presentation States, Key Image Notes, .wav files, Technologist Notes, Scanned Documents, even the Radiology Report as DICOM Objects, not only so they can be shared with other systems today, but also so they can easily be migrated and used in the next PACS. DICOM-conformance is always in the user’s best interest.
Now if a prospective buyer knew the negatives associated with proprietary data objects, would they choose a proprietary PACS anyway? Logic suggests that they should think twice. At the very least, if an organization goes ahead with the purchase of a PACS that still creates any proprietary data/object formats, that organization should negotiate a “no-cost” data migration clause in their contract that pins the cost of moving these proprietary objects to the next PACS on the vendor who has continued to choose NOT to conform to the standard.
Lack of DICOM conformance is a type of vendor lock. I believe that the PACS vendors still believe that anything that complicates moving to another vendor’s PACS may persuade the organization to stay with the incumbent. It’s time to make them pay for that strategy.